Method of making commutators



Aug 5, 1941- J. F. cULLlN 2,251,326 METHOD .OF MAKING COMMUTATOBS Filedsept. `7, 1957 2 sheets-sheet 1 @5 A y I uuuuuuuuuuuuuuuuuu-LluuuuMNH??'f2-1' HHHHIIHHIHHHHHH 2 Sheets-Sheet y2 J. F. CULLIN METHOD OF MAKINGCOMMUTATORS Filed Sept. 7, 1957 Aug 5, 1941.

Patented Aug. 5, 1941 2,251,326 METHOD oF MAKING coMMUrAroas Jasper F.Cullin, Detroit, Mich., assignor, by

mesne assignments, of vtwo-thirds to Lou Mervis, Chicago, Ill.

Application September 7, 1937, Serial No. 162,668

1 Claim.

matures of electrical machines and the manufacture thereof.

In the assembly of commutators, it is now common practice to provideoppositely-facing wedge or V-shaped rings adjacent the ends of, andinter-locking with, the segments of copper and mica to secure thesegments radially and circumferentially and to join the rings by aseparate metallic sleeve having integral radial flanges lapping theoutersides of the rings. Y

One object of the invention is to provide an improved method of.securing the segments together. 2

This object is attained by providing the wedgering members with abuttingtubularextensions or hub-,portions and welding the abutting edgestogether to secure the segments together. In this method, the rings usedare of such shape that they can be readily wrought or pressed in to thedesired shapes. By welding the abutting edges of the tubular extensionstogethen/ the rings are v united by a single operation and the separatesleeve and flanging heretofore necessary are dispensed with. Thisreduces the cost and simplifies the manufacture and results in forming aretaining sleeve which efficiently and securely retains the segments ofcopper or metal and insulating material in compact relation.

Another/object of the invention is to provide a method by which theassembly of the segments of copper and insulating strips and-the formingof the series of strips into an annular series, preparatory to receivingthe locking-rings, is greatly facilitated. This object is accomplishedby assembling the segmentsin a fixture and over a strip of material withan adhesive on one of its faces, whereby the segments will be held intheir placed order While they are being rolled into an annulus,preparatory to the assembly of the segments and the retaining-rings.

Another object of the invention is to provide a commutator which issimple in construction and composed of a small number of parts` whichcan be economically'manufactured and in which the segments andretaining-elements are efficiently secured in assembled relation.

Other objects of the invention will appear fromY n tion of a commutatormanufactured atcording'tol r to complete the commutator.

T-he invention relates to commutators for arthe improved method andembodying the invention. Fig. 2 is a view of the constituent parts ofthe commutator separated for illustrative pur- Fig. 3 is a plan of afixture for spacing the segments of a commutator for assembly. Fig. 4 isa plan of the fixture with a series of segments laid therein. Fig. 5 isa section on line 5-5 of Fig. 4. Fig. 6 is an elevation of a group ofsegments illustrating the manner of retaining the segments by theadhesive retaining strip, and assembling them into an annulus. Fig. .7is a vertical section of a press and Welder for illustrating the methodof uniting the retaining rings Fig. 8 is a vertical section illustratingthe method of assembling and welding the rings together. Fig. 9 is asection on line 9 9 of Fig. 8.

The inventionis' exemplified in a commutator,V

composed of an annular series of segments I0 of conducting material,such as copper, separated from one another by strips or segments II ofinsulating-material, such as mica. The inner portions f the ends ofsegments Ill and II have V-shaped notches I2 to form oppositely-inclinededges I3 whereby all of the segments may be locked together in anannular series by complementary wedge-rings I4 and I5 of steel.wedge-ring comprises an outer peripheral or tubular flange I6 a tubularinner or hub-portion Il and a conoidal side-wall I8 between the outerend of hub-portion I1 and the inner end of the' outer flangev I6. Thesides I8 of the rings I4 and I5 are oppositelyl inclined or inwardlydivergent, from theirouter flanges I6. Each retaining ring is insulatedfrom the copper segments I0 by a ring 20 of insulating material, such asmica. Each ring 20 comprises an outer tubular flange 2| and a conoidalportion 22 terminating in a bead 23. Rings 20 conform, respectively, tothe flanges I 6 and I'I and sides I8 of complementary retaining-rings I4and I5, respectively, and are ladapted to seat against and on theretainingrings. The flanges I'I on the rings I4 and I5 are extended sotheir inneredges I'Ia will substantially meet when the commutator isassembled, as hereinafter set forth. When the rings I4, I5 are securedvtogether end-to-end, the conoidal walls I8 will act as wedges and,through rings 20, will draw the segments I 0, II radially inward andinto close contact with one another and lock them together againstrelative longitudinal or radial movement. The edges IIa of rings I4 andI5 are welded together as hereinafter described to secure the segmentsin closely fitting relation. The commutator thus composed exemplifiesone Each which comprises a pair of complementary retaining-ringsdirectly joined together and which secure the segments without aseparately formed sleeve between the rings.

For arranging the copper and mica segments in alternating order, anxture is provided which comprises a ilat base 24 and side-bars 25 pro-`jecting upwardly from the longitudinal margins of, and fixed to, thebase. The spacing between bars 25 corresponds to the length of thesegments. A series of ribs 23 is formed on the top face of and alongeach side ci the base 24. These ribs are spaced apart longitudinally ofthe xture a distance equal to the thickness of the copper segments IIIand have a thickness corresponding substantially to the'thickness of themica segments. The number of ribs provided is suicient for receiving afull set of copper segments for a commutator. A strip 21 of flexiblematerial, such as stout paper having its top face provided with suitableadhesive 28, is laid on the top-face of the base 24 between thespacer-ribs 26, as indicated in Fig. 4. The copper segments I are thendropped between the spacer-ribs 26 until the entire group for acommutator has been laid and is held in the fixture. 'I'he bottom edgesof the segments will adhere to and be retained on the adhesive face oftape 21. i Segments or strips II are laid between the segments I0 and ontop of the spacer-ribs 26, as illustrated in Fig. 5. A portion of thestrip 21is left to project beyond one end of the series of assembledsegments.

When all of segments I0 and II have been laid in alternating relation inthe fixture and with the segments I I adhering to the strip 21, thelatter is flexed into a roll to fold the segments into an annulus or anannular series, as illustrated in dotted lines in Fig. 6. The projectingend of the strip 21 is lapped over, and secured by means of the adhesivethereon, to the other end of the strip, so the segments will be retainedtogether. in roll form. This exemplifies anA improved method of, andmeans for, assembling the segments into an annulus preparatory tosecuring them in the retaining-rings.

The mica rings 20 andthe retaining-rings I4, I5 are then assembled, withthe conoidal portions of the rings fitted into the recesses AI2 in theends of the segments I3, II, and with the inner edge I1l of flanges I1close together so that the rings can be welded together.

In uniting the rings I4, I5, topermanently secure the elements of thecommutator together, a hydraulic press is used to force theretainingrings and segments' together, and an electric Welder is used toweld the'rings together. This press comprises a base 31, verticalguide-rods 31, a cross-head 39 slidable on rods 31", and a ram 33 whichvis operable from a fluid pressure cylinder.

A base-plate 33,-which carries the lower electrode 3|, is slidablymounted on the base 31 toA permit the electrodes and commutator-assemblyto be placed under and removed from beneath the ram of the press.Electrode 3l is shaped to engage and conform to the inner and outerperipheries and the outer face of the conoidal side of ring I5. An upperelectrode 4I is shaped to engage and conform to the inner and outerperipheries, and the conoidal outer side of ring I4. The contiguous endsof the electrodes terminate adjacent the edges I1* of ring/s I4 and I5and are adapted, when electric current is passed through them, to

gether. The upper electrode 40 is adapted to be engaged by, or may besecured to, the lower heat the rings and weld said edges toend of ram33, to force commutator-assembly together 1ongitudinally between theelectrodes.

While the retaining-rings I4, I5 are being welded together, the segmentsare forced together by radial pressure. For this purpose, thecommutator-assembly is placed in a clamping-sleeve 33 composed ofarcuate sections. Outwardly extending stems 44 are fixed to the segments33, respectively, and guided in lugs 4I fixed to the base-plate 36.Abutments 42 with inclined and straight faces are fixed to thecross-head 39 and are adapted to engage the stems 44 to force thesections 33 inwardly before the rings I4 and I3 are welded together.Springs 43 are connected to the stems 44' and the lugs 4I to pull thesegments 33 outwardly when they are released by the abutments 42.

In producing the commutators according to the present method, theassembled segments and retaining-rings are placed in the sleeve 33 andon the lower electrode 3l. 'I'he upper electrode 40 is placed in theassembly. The base-plate 33 with the assembly and electrodes is moved toposition the upper electrode under the raised ram 33. The ram is thenlowered. During its downstrolre, abutment 42 will engage stems 40 andforce the sections of sleeve 33 radially inward and jam the segments l0,II together into tightfltting relation. As the ram is lowered, electrode40' is forced against ring I4 which will be pressed towards ring I5 andpress the mica-rings 20 and the segments together longitudinally. Whilethe commutator elements are thus pressed together radially andlongitudinally, an electric current will be passed through and acrossthe electrodes to weld the contiguous edges I1 of the rings I4, l5together, so that they will, in eiect, constitute a sleeve with integralsides and outer flanges, in which the inner ends of the segments aretightly and securely held against relative longitudinal or radialmovement. In welding the rings I4 and I5 together,they are subjected toa high temperature while the segments remain comparatively cool. As therings cool the whole assembly will be drawn tightly together, by reasonof the contraction of the rings, The armature assembly may then bemachined to its desired length. The `hub of the united rings is adaptedto be pressed on the armature-shaft 48. 'I'he wires may lbe connected tothe segments I0 in any suitable manner.

The invention exemplifies a method of making commutators in which theabutting edges of the t. retaining-rings are welded together topermanently secure the segments together. 'I'his dispenses with thenecessity lof separately forming end-rings and an intermediate sleevewith iianges for securing the rings together. It also exempliiies amethod of facilitating the arranging of the segments for rolling theminto an annulus preparatory to assembly with theretaining-rings orelements. The invention also exemplifies a commutator in which theretaining-rings have integral hub-portions which are adapted to beshrunk onto the commutator-shaft.

The inventionus not to be understood as restricted to the details setforth, since these may be modifiedl within the scope of the appendedclaim, without departing from the spirit and scope of the invention.

Having thus described the invention, what I claim as new and desire tosecure by Letters Patent is:

That improvementinfthe manufacture of commutators which comprises`assembling together an annular series o! segments having the innerportions of their ends provided with notches, assembling a pair of ringstogether axially with the segments between them, each ring being formedwith a side adapted to enter the notches in one end ofthe segments toradially interlock the segments and rings and with an integral tubularextension projecting inward from its side,l exerting pressure againstthe rines to force them together axially. subjecting the segments toinward radial pressure while the rings are-forced together, and weldingtogether the inner ends of the tubular extensions while the rings arepressed together and the segments are pressed radially inward, toautogenously unite the rings for permanently retaining the segmentstherebetween.

JASPER F. CULLD.

